[3] VERRILL—DREDGING APPARATUS OF U. 8. FISH COMMISSION. 6 
The largest size used by the Commission has the runners about 27 
inches high, made of flat iron, about 34 inches broad and #? of an inch 
thick; the beam is of hard wood, 18 feet long and about 6 inches in 
diameter; the net about 45 feet long. The net should be of very strong 
twine, the meshes about 24 inches in the upper part, but not more than 
4 inch toward the end. It is open at the lower end, and must be tied 
up securely when used. 
The rope for the “ bridle” is about 4 inches in circumference. ‘Those 
of smaller size have had the runners of relatively narrower and thinner 
iron, but it appears to be better to give increased weight to the runners, 
so that less weight will be required on the drag-rope. Moreover, the 
increased weight of the runners has a tendency to prevent the trawl 
fgom overturning in going down, an accident that occasionally happens 
where the currents are strong, or when the drag-rope is new and inclined 
to twist. The unusual breadth of the “shoe” of the runners is of ad- 
vantage in preventing the runners from sinking too deeply into the mud. 
The leaded bottom line should recede in the middle 8 to 10 feet. 
THE OTTER-TRAWL. 
Figures 3, 4, 5. 
The otter-trawls first used by the Fish Commission were imported from 
England, but those now in use were made in this country,* to order, after 
the English pattern. 
The side pieces (a, a, Fig. 3) consist of pieces of thick hard-wood plank, 
bound all around with flat bar-iron, $ inch thick. The rings (d, e, Fig. 4) 
to which the bridle-ropes are attached are of 32-inch iron, and should be 
attached to the wooden side-pieces by strong ropes, arranged as shown 
in Fig. 4. The bridle-rope is 4 inches in circumference. The dimen- 
sions of the otter-trawl now in use are as follows: 
fen sth Ore WwoOuen SIGe-PIECeS ~~...) a. sepsis ad) 1h 35 inches. 
Breadth of wooden side-pieces...-.-.-.....).08. 22025. cae Dan 8 
Thickness of wooden side-pieces. ....-. Be Stl Pict eiet oes: DOO IE 
Thickness of iron runners ....... FEY are Mom TA ESe 0x5: ie 
Width of iron runners...... geptosreeiseryt <4): {nia tiae o8s eon Whe 
Diameter of rings for bridle, inside ...-. SOEs ete rs DT 
Memon LODES (7,14; Hiss) emits) |2abicpan is i olade im Sub afte AD ve 
Heneith Of TOMES, (0,05 1G. 4)i2 2. Ltr se ltos debra Jeet eure s* 
Menethior ropes. 0) ds Bios 4). 20. .72)) > sis hte = tpt sete m4) FS 
‘RIG ULTERG EST 21 fe Re eS ea Eee eae en eae rere ae 40) feet. 
Breadth of net at mouth, when extended ...:. .......... poets 
inieadun Of side-pieces Of Net... 2 se oo ee Db 
emus: bridie-ropes, Gach half 2.2... -s.<<<ives ten 84. « 
& 
The leaded rope (d, d, ig. 3) should be longer than the upper rope (¢, ¢), 
so as to recede considerably behind the latter when in use. The figure 
* By the American Net and Twine Company, Boston, Mass. 
